Features: ` Integrated 0.1W
Power MOSFET
` 3V to 15V Operation
` Programmable
Electronic Circuit Breaker
` Digital Programmable
Current Limit from 0A to 3A
` Programmable
Maximum Output
Current from 0A to 4A
` Programmable On Time
` Fixed 2% Fault Duty Cycle
` Thermal Shutdown
` Fault Output Indicator
` Power SOIC PackagePinout
SpecificationsInput Supply Voltage
(VDD). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V
(VSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V
Maximum Differential Suppy (VDD - VSS). . . . . . . . . . . . . . . 18V
Maximum Supply Shunt Current . . . . . . . . . . . . . . . . . . . . 20mA
Fault Output Sink Current. . . . . . . . . . . . . . . . . . . . . . . . . .20mA
Fault Output Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7V
Output Current (DC) . . . . . . . . . . . . . . . . . . . . Internally Limited
TTL Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to 7V
Storage Temperature . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . 55°C to +150°C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C
Currents are positive into, negative out of the specified terminal.
Pulsed is defined as a less than 10% duty cycle with a maximum
duration of 500mS. Consult Packaging Section of Databook for
thermal limitations and considerations of packages.DescriptionThe UCC3920 Low RDSon Hot Swap Power Manager provides complete power management, hot swap capability, and circuit breaker functions. The only component needed to operate the device, other than supply bypassing, is the fault timing capacitor, CT. All control and housekeeping functions are integrated and externally programmable. These include the fault current level, maximum output sourcing current, maximum fault time, and start up delay. In the event of a constant fault, the internal fixed 2% duty cycle ratio limits the average output power.
The UCC3920 internal 3 bit DAC allows programming of the fault level current from 0mA to 500mA with 250mA resolution, and from 500mA to 3A with 500mA resolution. The IMAX control pin sets the maximum sourcing current to 1A above the fault level when driven low, and to a full 4A when driven high for applications which require fast output charging.
When the output current is below the fault level, the UCC3920 output MOSFET is switched on with a nominal resistance of 0.1W. When the output current exceeds the fault level or the maximum sourcing level, the output remains on, but the fault timer starts charging CT. Once CT charges to a preset threshold, the switch is turned off, and remains off for 50 times the programmed fault time. When the output current reaches the maximum sourcing level, the MOSFET transitions form a switch to a constant current source, regulating the output current at a constant level.
Other features of UCC3920 include an Open Drain Fault Output Indicator, Thermal Shutdown, Undervoltage Lockout, 3V to 15V operation, and a low thermal resistance Small Outline Power Package. All level shifting is done internally, which means that the DAC, IMAX and Shutdown Inputs can be driven form the logic supply. The fault output is also referenced to the logic GND, so this can easily interface back to the logic supply.
UCC3920 Data Sheet
